Paint testing machine



July 5, 1955 H. R. HARLAN PAINT TESTING MACHINE 2 Sheets-Sheet 1 FiledAug. 25, 1952 l/VVEN TOR N I? R Z A v 0& a R m United States Patent2,712,235 PAINT TESTING MACHINE Harold a. HarlanfSan Francisco, Calif.Application August 25,1952, Serial No. 306,148 8 Claims. (Cl. 73-150This invention relates toa machine for testing physical characteristicsof paints and the like. More particularly, it relates to a testingmachine adapted to test the brushability of paints, varnishes, lacquersand the like.

In one type of known paint testing device intended for the generalpurpose indicated, a body of paint in a vessel is.stirred with paddlesrotating in the body of paint, and the time elapsing for the paddles tocomplete, for example, one hundred revolutions is noted. The lapsed timeserves as an indication of the viscosity, and to some degree of thebrushability of the paint. However, viscosity is only one factor indetermining the brushability of a paint, by which is meant the ease orditficulty with which a paint can be applied to a surface with a brush.Brushability may also be defined as the resistance or drag of a paint asit is brushed over a surface. It is, of course, this resistance or dragwhich is of practical importance to a painter. Thus, thequality of apainting job, and the length of time required to complete a job, dependto a great extent upon the brushability of a paint or other similarcoating material. a

It is an object of the present invention to provide an improved painttesting device for the purpose described.

It is a further object of the invention to provide. a paint testingdevice whichis adapted to measure the brushability, as distinguishedfrom measuring merely the viscosity, of a paint or other similar coatingmaterial.

it is a still further and a particular object of the inven; tion toprovide a paint testing machine of the-character and for the purposedescribed which is adapted to measure the brushability of a paint and toprovide data "which correlate reliably with actual painting practice.

It is a further particular object of the invention to provide a painttesting machine of the character and for the purpose described which issimple in its construction and operation and which embodies adjustablefeatures 4 as described hereinafter.

These and other objects of the invention will be apparent from theensuingdescription and the appended claims. l

Certain forms which the invention may assume are illustrated by way ofexample in the accompanying drawings, and are described in detailhereinafter.

In the drawings: 1

Figure l is a perspective view of one form of paint testing deviceconstructed in accordance with the present invention.

Figure 2 is a plan view, on a larger scale, of the paint vessel and thebrush assembly of Figure 1.

Figure 3 is a vertical section taken through the paint vessel and alongthe line Ill-III of Figure 2.

Figure 4 is a top plan view of an alternative form of the brushassembly. V

Figure 5' is a view in side elevation of an alternative and preferredform of paint testing machine constructed in accordance with theinvention and including a motor drive for the paint vessel. 1

. thereof.

2,712,225 Patented J uly- 5, 1955 2 Figure 6 is a fragmentaryelevationalview of the uppermost portion as seen from the right of Figure 5. I

Figure 7 is a fragmentary top plan view of the pivot rod, .a$ seen alongtheline VII-VII of Figure 5.

, Figure 8 is a plan view of the paint vessel and brushasSembIyofFigureIS asseen along the line VIIIVIII Referring now to thedrawings, and more parti cularly to Figures 1, 2 andS, the machine ordevice as a whole is indicated bylthe numeral 10 and it comprises a flatbase 11, to which are fixed spaced upright rods ar stan chions 12. Therods 12 support a driving element 13 of known construction, including agear case 14 within which suitable gearing (not shown) is disposed.Thisgearing is drivenby a vertical shaft 15 to which is fixed a windingdrum 16. The drum 16"and shaftlS are driven by a weight. 17 which isfixed to one end of a cord 18. The

cord is led over a guide pulley 19 rotatably mounted on a bracket 20,and at its other end is fixed to the drum 16.. A handle 21 is providedfor winding the cord 18? is provided to' on the drum, and a releasemember 22 release the drum.

The driving element 13 also includes a shaft 25 which is driven by thegearing in gear. case 14, and an indicator 26 which visually shows'therevolutions of the'shaft 25-;

The shaft 25 is coupled at its lower end by means including a set screw28'to the upper. end of a shaft 29,. the

lower end of which is fixed to a brush assembly 30. The brush assembly30, which is best shown in Figures 2 and 3, is mounted to rotate in andconcentrically of a cylin-,

drical paint vessel 31, the interior surface of which presents a uniformsurface for; receiving a test film. The

vessel 31 rests upon a base 32. (see Figure 1) which is adjustablymounted on and fixed to one of the upright. frame rods 12 by a setscrew'34 or any other suitable means.

The brush-assembly comprises a flat, elongated bracket 35 havlng.;adownwardly'extending collar orv sleeve 35a'which is adjustably fixed tothe shaft 29 by ing member 46 and cap screws 47. Each of the brushes44-is also provided with a sheathing 48 which encompasses the heel ofthe brush" and is received between the.

angle bracket 37 and the clamping member 46.

In operation, a body"of paint or other liquid whose brushability is tobe tested is placed in the paint vessel 31 to a level not to exceed thatindicated by the numeral 49 in Figure 3. The movable base 32 is thenadjusted so that the brush. assembly 30 will rotate within the vesselabove the liquid level 49 and is then held in the adjusted positionbythe set screw .34. The. brushes, 0f the brush assembly areimmersed inthe liquid and rotated therein to thoroughly wet the brushes. Followingthis the vessel 31 is raised by hand and lowered to the baseseveraltimes so that the brushes during rotation will apply a film ofpaint or other liquid, to .the inside wall above the liquid level. Afterthe brushes are thoroughly wet and the liquid film has been applied tothe inner surface of the wall above the liquid level, the vessel 31 islowered to its position on the base 32 which centers it precisely withthe axis of rotation of shaft 29. The spindle 16 is rotated by means ofa handle 21, in a clockwise direction, to lift the counterweight-17until the pointer 26a on themeter 26 is at zero or any otherconvenientstarting point. The spindle ,16 is then released by means of may beallowed one to 3 the release member 22 to anew tli eeiiiitetweighr to"fall freely. By this means the shaft 29 and the brush assembly 343 arerotated with the wet brushes contacting the coated surface above the l-iuidlevel in th'ejvssel The time elapsing for a given riurriliefrevolutions, e. g., ten revolutions, is clocked by rhansofa stop watchor in any other suitable manner. This elapsed nine co'nstitutes ameasure of the brushabil'ity ofthe pa nt or other liquid. Thus, a paintwhich has difii'cult" brushability will require a greater time thanuneasily able paint. Fora more precise determination, the brushes thecount and timing of a selected number of rotations is made. The numberof rotations berequired to indicate brushability accurately, may variedat the option of the operator so long as a standardis' estabhshed, butit has been found that the smallest number of revolu tions which willgive reproducible within the shortest period of time, is the mostsatisfactory for determining brushability. Increased number ofrevolutions and longer periods of time may produce erratic results dueto solvent evaporationor latent viscos1ty characteristics which do notordinarily exist during brush application of coatings. I V I v IReferring now to Figures to 8, and more particularly to Figure 5, amotor driven paint test ng device is there illustrated and is generallydesignated by the numetal 54 It comprises a flat base 51 to which atubular standard 52 is fixed which slidably receives a rod 53 and isprovided with a set screw 54 to clamp the rod 1 53 in a suitableposition. The device also includes a cylindrical paint vessel 55 whichis seated on a rotatable base 56 and is keyed thereto bymeans of a pin56a. The base 56 is formed with a collar 57 which is journalled'in aframework 58. The vessel 55 is rotated by means of a motor 60, which isclamped to the collar 57 by means of a set screw 63. A switch 64 isprovided'for operating the motor. p 7' A brush assembly 30 is alsoprovided which, as illustrated, is identical with that shown in Figuresz e l 3. It may, of course, be a four-brush assembly such as-shown inFigure 4. The brush assembly 30 is mounted at the lower'end of a shaft65, the upper end of which is coupled by'rneans of a coupling"member'tidand a set screw 61 to a s'haft'68. The shaft 68 is journalledin a bearing 69 formed in a bracket 70 which is slidably mounted on therod 53 by means of a sleeve 71. The sleeve 71' and bracket 70 areclampedin a suitable position by means of a set screw 71a. 7 H bracket70 and is fixed re a pulley' 7; by means of s set screw 73. A cord '74has one end rhea to the pulley 7 2 and is led over a guide pulley 75"rotatably mounted on a bracket '76, and the cord 74 is provided with aHook 77 at its other end which engagesa pivot'rod '78. The

pivot rod 78 extends t'hrough a slecye'80 and isclamp'e'd thereto bymeans" of a set screw 81. The sleeve 8t) 15 rotatable on a pin 82" whichis'fixed to an eaf'or bracket s3 formed on the sleeve 71. The left-handend or the pivot rod' 78, as viewed in Figure 5', is threaded at 84 toreceive threaded counterweights 85; At its other or right-hand end thepivot rod 78i's formed witha scale9'0 see Figure 7) and it slidablyreceives a weight 9 1. v In operation the device described above and"illustrated in Figures 5 to 8 functionsas'follows:

Paint or other liquid which is to be tested is placed in the vessel 55;care being eiiercised' that the liquid level does not prevent the freerotation er the'brush' assembly 30' within the vessel and above theliquid level. The brush assembly 30 is coupled to the shaft68 ata pointadjacent its lower end and the bracket 70 and sleeve 71 ar adjusted andmarked in position so thatthe brushes 4 4 will rotate above the liquidlevel and engageitlie inner ates of the wall of the vessel 55. Theswitch 64 is then turned on to o erate the motor 60 'which will, ofcourse,

four complete rotations before The shaft 68' extends above the 4 themarked adjusted position. While the assembly is thus loosened, thebracket 71 is raised and lowered several times so that the wet brusheswill apply a film of liquid to the inner surface of the vessel 55 abovethe liquid level. When the brushes are thoroughly wet and a film hasbeen established above the liquid level, the motor is shut off and thesleeve 71 returned to the adjusted position and held in that position.The weight 91 is then set at zero or at any other suitable ieferehcepoint on the scale 9'0l The counterweights' 85 are'adjusted to level thepivot rod 78 and maintain it in horizontal position while" the brushassemblyis at rest. The switch is then turned on to operate the motorand revolve the vessel 55. The brushes 44 of the brush assembly 30 willsweep the inner surface of the vessel 55 and engaging the film on thewall above the liquid level and will exert a certain degree of dragdepending upon the brushability of the paint or the shearingforce'r'eqt'iifed to move the brushes ove'r the film'; This dragwilltend to rotate the brush assembly 30 andwith l the" shaft 65'. Assumi gthe rotation of the brush assembly 30 to be counterclock wiseas viewedin Figure 8, rotation of the shaft 65 will be in the same" direction andwill'tend to wind the" chin 74 abeut'nie pulley" 72. I This will tendt'o'lift' the right liondend of the rod 78, that is, to rotate it aboutthe axis of the" ivot pin 82 in counte'r'clockwis'e direction; Meanwhile, the operator will adjust the weight 91 to counteract the drag ofthe brushes 44 audio level oil? the pivot rod 78. In practice, the rod78 will oscillate about a' median position, and the weight 91 will beadjusted so that this median position is horizontal. The reading ofweight 9 i. e'., the point onthe scale at which the pivot rod'91 islevel, will provide ainfeasure of the brushability of the paint. Thus,the" weight 91' will require" movement outwardly to a greater scalereading for a difi icultly' brushablepa'int than for an easil-briisheble paint.

In employing either of the paint testing devices illus tratedin Figuresland 5', it is preferred to empl y a standar ei-ife'r'e ehee liquid tocalibrate the iiieterzs er the'device of Figure 1 or the scale 90 of thedevice of Fi re; 5. A var'iety of suitable reference liquids areavailable, among which may be mentioned glyeerinej, heavy lubricatingoil, castor oil and strained lard oil.

1' These and other similar liquid materials are commercial'ly availablein iaridardizedrorm t provide a standar rferehc'e liquid. If paints"having a loiv de ree of brushabilityare being tested, areferehceli'quidbf' relatively low brus'h ability' is used, while areference liquid having a high degree of bru's'liability will. beemployed for tes paints having a high degree of unreliability. Eitherrorhiff'devicec'a'n be calibrated ever a consider able raneef'bnrshsbiliry, nierly'by several reference liquids representing high,ni 111m and'low d6 g're'es ofbrushability. piactic'e, there" iscicellent correlation between readings of the meter 26 or the scale 90,and the experience of professional painters withregain to-the'ease'ordifliciilty of a'ppl'icationof pai rr'fs.

As" illustrated in the; drawings, the brushes 44' can be adjusted tofdrm'an'y desired angle with the interior wall of the paint vessel. Itis preferred to adjust the brushes to make a constant and even contactwith illewalls of the paint vessel, to spread-an even fihnotpaiiir,and-to ass smoothly over the film of paint. They should not be set" atan angle tocreate a considerable drag or braking acrotate the vessel 55.The sleeve 71 is then loosened from brushes; a given set of brushes willchange its character 5 istics after long use, and a new brush will nothave the same brushing characteristics as an old brush for which it hasbeen substituted. While brush assemblies having two and four brushes areshown herein, it is to understood that any number of brushes may beused.

To compensate for these variations, a new set of brushes, for example,will be tested in a reference liquid and the counterweight 17 of thedevice of Figure l, or the counterweights 85 of the device of Figure 5,will be re-adjusted as necessary to produce a reading on the counter 26or the scale 90 which corresponds exactly to the reading obtained withthe old brushes which have been replaced.

A cover 92 may be used for the paint vessels 31 and 55 as shown inFigure 3, to limit evaporation in case highly volatile elements areinvolved, and, in any event, to minimize evaporation. An opening 93 isprovided therein to permit the passage of shaft 29 or 65 therethroughwithout interference with rotation.

It will thus be apparent that a paint testing device has been providedwhich is simple in its construction and operation and which operatesupon the principle of rela tive sweeping movement of a brush or the likeover a film of paint on a solid surface, thus closely simulating actualpainting practice. The resistance to this sweeping movement, which maybe manifested by the speed of relative movement, or by the forcerequired to prevent movement of one of the elements, provides anaccurate measure of brushability.

In both its modifications as illustrated in the drawings and describedhereinabove, the paint testing device of the present inventionaccurately measures brushability and not merely the viscosity of apaint. This is of major importance in that two paints of the sameviscosity may have widely different brushing characteristics. The deviceis very simple to operate and requires only a minimum of calibration. Asexplained, the brushes are easily adjustable at the outset to producethe proper degreeof drag, and they are easily readjusted aftersubstitution of new brushes to the end that the brushing characteristicsare kept constant.

The term paint is used throughout as a convenient general term. Thedevice of this invention is equally applicable to testing lacquers,varnishes and other coating materials which are intended to be appliedby a brush or roller.

I claim:

1. A testing device of the character described for testing thebrushability of a liquid on a solid surface, which comprises acylindrical vessel for receiving liquid and providing a uniform testsurface for a film of test liquid above the liquid level, bristledbrushing means for applying a film to said surface, means for producingrelative movement of said brushing means and test surface with novertical load and calibrated means for measuring resistance to suchrelative movement offered by the drag of said brushing means on saidfilm.

2. A testing device of the character described for testing thebrushability of a liquid on a solid surface, which comprises acylindrical vessel for receiving liquid and providing a uniform testsurface for a film of test liquid above the liquid level, bristledbrushing means for applying a test film to said surface, means formoving said brushing means to contact and traverse said film with novertical load and calibrated means for measuring resistance to suchmovement offered by the drag of said brushing means on said film.

3. A testing device of the character described for testing thebrushability of a liquid on a solid surface, which comprises acylindrical vessel for receiving liquid and providing a uniform testsurface for a film of test liquid above the liquid level bristledbrushing means for spreading a film on said surface, means for producingmovement of said test surface relative to said brushing means with novertical load and means for measuring the resistance to such movementoffered by the drag of said brushing means on said film.

4. A testing device of the character described for testing thebrushability of a liquid on a solid surface which comprises acylindrical vessel for receiving liquid and providing a test surface fora film of test liquid above the liquid level, bristled brushing meansfor spreading said film on said surface, means for moving said brushingmeans across said surface through said film with substantially novertical load, and means for measuring the rate of movement thereof andthereby measuring the resistance to such movement oifered by the drag ofsaid brushing means through said film.

5. A testing device of the character described comprising a cylindricalvessel for holding a test liquid and providing a surface for a test filmthereof above the liquid level, means for rotating said vessel, bristledbrush means, means mounting said brush means axially within said vesseland in brushing contact with its said test surface with substantially novertical load, and means for measuring the force tending to rotate saidbrush means, said rneasuring means comprising a lever, an adjustablecounterweight carried by said lever for opposing said force, and a scalecooperable with said counterweight to indicate said force.

6. A testing device of the character described comprising a cylindricalvessel for holding a test liquid and providing a surface for a test filmthereof above the liquid level, means for rotating said vessel, abristled brushassembly comprising a plurality of radially arrangedbrushes, means including a shaft for mounting said brush assemblyaxially within said vessel in brushing contact with the interior surfacethereof with substantially no vertical load, a lever having a fulcrum, acounterweight carrier by said lever, a scale cooperable with saidcounterweight, and means operatively connecting said shaft with saidlever to rock the lever when said shaft is rotated, said counterweightbeing adjustable and cooperable with said scale to counterbalance theforce tending to rotate the shaft and to indicate the degree of saidforce.

7. A brush assembly for a paint testing device comprising a shaft, abristled brush in a plane at right angles to the axis of said shaft, andmeans mounting the brush on the shaft and adjustable to vary the angleof the brush in said plane relatively to the shaft.

8. A brush assembly for a paint testing device comprising a shaft, aplurality of brushes, and means mounting said brushes equiangularlyabout the axis of said shaft in a plane at right angles to the axis ofthe shaft.

References Cited in the file of this patent UNITED STATES PATENTS2,016,779 Hardgrove Oct. 8, 1935 2,020,565 Neely Nov. 12, 1935 2,036,315Barnhart Apr. 7, 1936 2,196,613 Shaw Apr. 9, 1940 2,519,259 Liebman Aug.15, 1950

